Underreamer



` Feb. 2, 1932.

F. c. FARMER UNDERREAMR Filed Maren A18, 1930 A TTORNEYS.

FitnNois C. FARMER, or Los' Y ik Los 'ANeELns, oAL1roi-ti\iin be safelyVsubjected to heavy Patented Feb. 2, 1932 ANGELES, CALIFORNIA, essie-NoiaTO `TOI-11T GRANT, OF

' L UNDERREAMER Application' inea nalen 1t, 1930. seriaii'N. 436,760.

i This' invention relates to an underreainer drill adapted for use ingeneral*l in drilling operations whereverit is desired to'enlarge.

the diameter of the Well. borefbeneath "the lower end ofthe well casing.v

Amongtheobjects of the invention are'tol y being `shown inv thedrawings., QJThese reprovide a tool of the character stated which willbe an improvementup'on others -ofits class withl respect to'efliciencyand dependability'of operation; one in which the vcjiu'sting elementsmay be more readily and'conveniently inserted, and removed after theyhave become' worn in order that "new-cutting 'ele'- ments may beinserted; and a general con.- struction which improves upon the priordevicesof theV` class with respect to various other' details. y j f fAmong theobjects of the inventionl are -to provide improved means for'supporting the cutter shafts in such a manne'rthat they may strainduring drilling operations. Y

lYet another object of the invention isi-to provide superior means formoving the reamel ing elementsA from anormal sheltered, retracted,inoperative position outwardly intocontact withthe portion ofthe wellbore which isto'bereamed away.y y

Referring in detailto the accompanying drawings7 which illustrate whatis at present deemed to be a'preferred embodiment of the invention, f 'fi `Fig. 1-is a side elevation of the complete tool mounted inpositionfor use, laportion of the view beingshown in mid-section. Fig. 2' is aside elevation ofthe centrall portion ofl Fig. 1, looking at said Fig. 1from right to left, Y 'the cutting' elements being shown inafdiflerentvposition. f f f `Fig. 3 isxa sectional detail-showing'one ofthecutting elements inthesame position as in Fig. 2.5 v

ytig. 4 isa cross sectionon line of Fig. 1. f i' u F ig. 5 is' across'section on line5-'5 of li`i,g.2l"V

Figu is a sectionaldetail of one of the reaming elements together'wi-thits shaft and adjacent parts. Y 'y f Referring in detail'Vto-thedrawi-ngs, thel it is united to the usual tool joint'13.` TheA.body portion of the tool is provided with a l 'plurality ofrecesses15whichl are equally spacedfrom each other, three of said recessescesses are eachad'apted to shelter one' of fthe composite reamingelements 16 which will laterbe described. ySaid recesses 1 5 aredesirably,"y as viewed in cross section7 of a broad shallow nature asshownin Fig. 5 to avoid clogging, but the'invention is not limitedv to'any particular shape of recess 15.

Each ofthe composite reamers 16 com prises a main central cutter 17 afrusto-coni cal upperv cutter 18 and a cylindrical-lower Icutter19,thecentral cutter 17 being bevelled at 20/adjacent to said cutter19.17T-hese cut* The upper @mi of 'Shaft 22 is .provided .with

va flattened head 23 lwhereby,-by means of a pin-24, it is pivotallysecured to the outer bifurcate'd end "of a link 25,'th'e upper end ofsaid link 25 being in turn'pivotally secured to the body of the tool bymeans of a pivot-pin or bar 26. Each link 25 hasa swing through alimited arc, the upward rmovement of said 4link being 'limited by ashoulder 27 which is positioned toy arrest the movement of. said linkafter thepivot pin f ,tool is provided with a cylindrical bodyfporlVtion 10 yhaving a shank portion 11 whereby 22 whereon they f 24 hasreached ya point kslightly lalcove the level'o'f thepivot-pin 26. 'Theouter end portion'of said link isv preferably provided with a curvedface 29.V f f f The inner end portion of' saidA link is 'pro- "videdwith a curved face 30;` These. curved faces 29 nand 30 are formed asa'rcs having Lforth'eir respective centers the pivots A24and 126.r Theface is shaped to have a working lit upon a curved facev or recess81formed 'at the upper end'of the recess 15 in order to provide anabutment to support' thelink "and relieve pressure from the pivot rpiny26 during reaming, as will hereinafter more fully appean At the lowerend of each cutting device 16 is locatedva follower whichlis seated withel. l

a working lit in a circular recess or pocket 36 provided therefor in thebody portion of the tool beneath the main recess 15. rlhe lower end offollower 35 is recessed at 35a to receive a compression spring 37. Theupper end of follower 35v is recessed at 352) to rece'ive'vthe lowerportion of shaft 22 which projects beneaththe composite cutting element16 mounted thereon. This recess 35?) is widened toward its mouth so asto permit 'the yshaft 22 to swing from one to the other of the positionsshown in Figs. 1 and 3.`

Longitudinally through the entire tool eX- tends a water supply passageed At the lower end of the tocl a fish-tail bitfll is shown attached bya conventionalshank a2, or other drilling n ieans'inay be substitutedfor said fish-tait bit. With said passage 10 communicates-radial ductsor. passages 413, there being a passage. 413.; tofsupply waterto eaclrofthe Inainrecessesl., A .Y I

YReferring to; further details regarding the 'means for pivotallyattaching the linlis 25,

each of the VpiVQt pins of the links 25 fits -iirto a hole. 2671,provided therefor as indi-l cated inFig. 41, said hole being bored inthe direction of a chord with respect tothe cylindrical body-of thetool,'but not being drilled quite-through vthe tool', there being adiavmetricallyreduced hole 262' which leads from thebase. of hole 26h tothe adjacent side of -theitoo1- f f Thepin, 26 is driven tightly intothe hole 261i sothat it wilt not be accidently displaced. -Vllli n'it-is, desired to remove the pin 26, a

n mail orothor suitablotool is inserted through the hole 26a' and isthen driven against the .ond olfI Said pnin order to loosen 'it'.

Afterv the/pin has thus been loosened it may. readily be removedpermitting the link 25- together with shaft 22 and composite figeamingelement 16 to. be completely` remoyed soI that zthe cutters 19, 17or-18, may one. or all be removed and replaced;withl new cutters,

. 1in addition, toJ the ducts or passages 4:3 which havealready beendescribed, addition- .al ducts orfpassages 5 0 are provided, one vof'lower end-portion otsad` roces-S in. order to v.supply liquid pressurethereto from. the pas- ;Slg'e 410; thus to` aid the Spring iii-moving'.thereamlg elellnt 1,3 up tothe operative yposition,shown in Figli Theupper passage lili-is,desi-rably madel smaller than the lower o ssaoe50because said lower assaoe is desig-ned to, freely supply hydraulicpressure beneath tho follower 35but the u )per l P sage L13 will performits cleansingl function morel effectivelyifg Water. passes4therethrougi1 in morerapidly moving stream.

lessees The spring element 37 which has already been described,comprises a spring` of as greatacompressive power as can be used'with`out interfering with the lowering of the tool into the well, that is tosay, the rotary reamu ing elements 16 mustnot be forced Jtoo violentlyinto .engagement withftheisides of the welll casing and yet the spring37 should be strong enough to b e depended upon to move said elements upto the operati-ye "position when said spring` isA aided by the hydraulicpressure supplied through passage 50 beneath the follower 35.

The frustrofconical cutter 18 around its baseportion is ofthe samediameter as the main Cutter 17, and normollyseats uponfthe yupper end;of sai-d cutter17. This construction adaptsthe reaming element as@ywlfiolie to smoothly and effectively engage the ignaterial to beroamed. as eachreamging device Y isforced upward: to its operative;position. A

The short cylindricalcutter; 19 isv of' a smaller diameter than the mehrcutter 17 in order that said :cutter 19i'may, as ,nearly as.

possible .llf the upper end of the roeoss and may therefore, more.effectively koop saidrecess from becoming clogged up with materialsdetached vby, the ream-ing operaertending therearound filled with apack-ing of anyapproved kind, in, orderto causevv the hydraulic pressurebelowf the follower tofact thereupon effectively.

vided adjacent its lower end witha deepened lportion15a in ordertofsa-feguard against 1n operation, the tool is 'lowered into vthe wellcasing and as therotary roaming elements 16 enterlthe top `of thewellcasing they ,areinanually depressed, if need be, against theopposition ofsprings37 in order that the 'toolmaybesmootyhly fedy intothe well; cas- The tool Visf-then completely lowered into the wellYuntil the reaming elements 1 6 arrive at the position to. beA used forunderreaming. Then liquid pressure is supplied through the maiii,passage10v andg ductl 50 thus to aid the spring 37 inraising the follower;3,5,y of" eachv of said. reainingdevices 16,

.thereby foroiI-15-tY Marthe-'drill shafts. y'22410 the position shownin Fig. 1 wherein the pivot U in4 theouter portion; of each link25occu'The follower 35 a circularvr recess- 3511L loo of the recesses 15isdesire-bly,proi the other end portion ofsaid link.

pies a higher position than pivot 26 through position of the links theupper edges of the links abut against the shoulders 27 while the innerends of said links rest aga-inst the` face 30 provided therefor. Hencewhen the tool `is'rotated the reaming elements 16 are supported in averysubstantial manner attheir upper ends and no mattery `howrheavy a forceis applied to them in a. radiallyinward di' rection, they maintain theiroperative position by reason of the pivot pins 24 being positioned abovedead center with relation to the pivot pins.

When a follower 35 is inthe depressed position illustrated in Figpk,4the pressure of the spring37 thereagainst is the greatest.

n Therefore, since said spring safeguards against the follower becomingstuck fin its most depressed or starting position, the

springvand hydraulic pressure means cooperate to improve thefunctioningof the device. Y

Claim:-

An underreaming tool comprising an elon` gated body portion adapted tobe lowered through a well casing, a cylindrical cutter mounted adjacentsaid body portion and po'- v sitioned to perform an yunderreamingoperation7 said cutter being mounted upon ay shaft which extendslengthwise of said body, a

link pivotally connecting said shaft with said body, a spring to forcesaid shaft'length-v` wise of said body and thereby cause said link toforce said shaft radially outward from said body, a follower againstwhich said spring operates to move said shaft in the direction of itslength as aforesaid, and means to supply hydraulic pressure to saidfollower to supplement the aotionof said spring thereagainst. v

In testimony whereof I hereunto aiix my signature.

5 FRANCIS C. FARMER.

In this

